The proposed mass spectrometer will be utilized to characterize synthetic samples, biogenic compounds, and natural products which are of biomedical importance. The following NIH are related projects are in progress at the Health Center of the University of Pittsburgh, and will be benefited from the acquisition of the proposed instrument: 1. Biochemistry and pharmacology of Trace Amines in Brain. 2. Psychotropic Drugs and Aromatic Amino Acid Metabolism. 3. Tranylcypromine vs Lithium in Bipolar I Depression. 4. Characterization of N-terminus Blocked Peptides. 5. Structure and Function of Thioredoxin and Glutaredoxin. 6. Synthesis of Antagonists of Gastrin Releasing Peptide for the control of Small Cell Lung Cancer. 7. The Isolation and Identification of Bisbenylisoquinoline Alkaloids with Potential Biological Activity from Higher plants. 8. Interaction of Antiviral Agents with Myeloperoxidase. 9. Drug Disposition in Liver Transplant Recipients. lO.Characterization of Peptidyl Steroids and their Metabolites to be used as Antiarrhythmic Agents. 11. AIDS Treatment Evaluation Unit - Drugs and Metabolism